Disk unit having at least one limit switch for detecting a size of an inserted disk

ABSTRACT

A disk unit wherein a disk is inserted by a plurality of arms, the arms being able to convey two types of disks different in diameter while supporting an outer periphery edge of each of the disks. A disk is loaded to the interior of the disk unit by automatic loading, and a disk accommodated in the interior of the disk unit is unloaded to the exterior of the disk unit. The disk unit comprises a limit switch, the limit switch being actuated by an arm that is pressed by an outer periphery edge of a large diameter disk or a small diameter disk upon insertion of the disk from a slot of a bezel. The insertion of the large diameter disk or the small diameter disk is determined on the basis of the state of operation of the limit switch.

BACKGROUND

1. Field of the Invention

The present invention relates to a disk unit for driving an optical disk(e.g., CD-R/RW, DVD-R/-RW/RAM/+R/+RW) as a recording medium that storesa large amount of information in information systems such as variouscomputer systems.

2. Description of the Prior Art

The disk unit incorporated, for example, in a personal computer isusually provided with a disk tray loaded with a disk, the disk traybeing constructed so as to move forward and backward. The disk loaded onthe disk tray is driven within a body of the disk unit to perform reador write of information.

On the other hand, as a disk unit not using such a disk tray, a slot-intype disk unit tends to be adopted more and more. The slot-in type diskunit is suitable for the reduction in thickness and size of personalcomputers. In the slot-in type disk unit, the disk tray is not used forload and unload of a disk with respect to the unit body, so when anoperator inserts the greater part of the disk into a slot, a loadingmechanism installed in the unit body operates and loads the diskautomatically.

FIGS. 53 and 54 show the construction and operation modes of a loadingmechanism in a conventional slot-in type disk unit. According to theillustrated construction, when an operator inserts a disk D into a slot,the disk D reaches its position shown in FIG. 53 while its heightdirection and right and left positions are restricted by a pin 100 aprovided at a tip of a first pivotable member 100 and also by right andleft guide members 101, 102 and further restricted halfway by a pin 103a provided at a tip of a second pivotable member 103.

At this time, the pin 100 a at the tip of the first pivotable member 100is pushed by the disk D and the first pivotable member 100 rotates inthe direction of arrow 100A. Likewise, the pin 103 a at the tip of thesecond pivotable member 103 is pushed by the disk D and the secondpivotable member 103 rotates in the direction of arrow 103A. Further, aswitch lever 104 is pushed against an end portion of the secondpivotable member 103 and rotates in the direction of arrow 104A, therebyactuating a detection switch 105.

Upon operation of the detection switch 105, drive means 106 startsoperating and a first slide member 107 starts moving in the direction ofarrow 107A. An end of the first slide member 107 and an end of a secondslide member 108 are connected together through a slide connectingmember 109 that is pivotably supported by a pin 110. Consequently, thesecond slide member 108 moves forward in the direction of arrow 108A insynchronism with retreat of the first slide member 107.

Once the first slide member 107 starts to retreat, a driven pin 100 b ofthe first pivotable member 100 that is cantilevered by the first slidemember 107 is guided by a cam groove 107 a of the first slide member107, so that the pivotable member 100 rotates in the direction of arrow108B around a fulcrum 100 c, whereby the pin 100 a at the tip of thefirst pivotable member 100 conveys the disk D in the direction of arrow107A until abutment against pins 111 a and 111 b of a disk positioningmember 111.

At this time, the pin 103 a of the second pivotable member 103 rotatesin the direction of arrow 103A and therefore moves in the arrow 103Adirection in synchronism with the pin 100 a provided at the tip of thefirst pivotable member 100 while supporting the disk D. Then, afterabutment of the disk D against the pins 111 a and 111 b of the diskpositioning member 111, the pin 103 a rotates to a position spaced alittle from the disk D.

The above is an operation mode of the loading mechanism in case ofloading the disk D into the disk unit. The operation mode of the loadingmechanism in case of unloading the disk D to the exterior of the diskunit is reverse to the above operation mode. More specifically, when thedrive means 106 is turned ON in the opposite direction in accordancewith an unloading command in a state in which the disk D is at apredetermined position in the interior of the disk unit as shown in FIG.54, the first slide member 107 starts to move forward in the directionof arrow 107B and, in synchronism therewith, the second slide member 108connected to the slide connecting member 109 starts to retreat in thedirection of arrow 108B. Consequently, the first pivotable member 100rotates in the direction of arrow 100A and the second pivotable member103 rotates in the direction of arrow 103B, so that the disk D isunloaded to the exterior of the disk unit while being supported by thepins 100 a and 103 a provided respectively at the tips of thosepivotable members.

The disk D loaded into the disk unit is clamped by a clamp head 112 thatis adapted to move vertically at a predetermined position. The clamphead 112 is integral with a turntable 113 fixed to a drive shaft of aspindle motor 114. The spindle motor 114 is disposed on a frame member(not shown), which frame member is moved vertically by a lift mechanism(see, for example, Japanese Patent Laid-Open Publication No.2002-117604).

In the disk unit configured as above, in order to effect a cooperativeoperation of both first pivotable member 100 and second pivotable member103, the first slide member 107 and the second slide member 108 areconnected with each other through the slide connecting member 109 so asto synchronize their forward and backward movements. Therefore, thepositions in the course of conveyance of the pins 100 a and 103 aprovided respectively at the tips of the first and second pivotablemembers 100, 103 must be determined on the basis of an outer peripheryedge of a disk of a specific diameter.

Disks defined by the standard applied to such a disk unit as the abovedisk unit are generally called 12 cm disk and 8 cm disk, the formerbeing the highest in versatility. Driving a disk of such a differentdiameter in a disk tray type disk unit can be done by only loading thedisk to a corresponding groove formed in a disk tray. However, in thedisk unit having such a mechanism as disclosed in Japanese PatentLaid-Open Publication No. 2002-117604, a pivoting range of the firstpivotable member 100 and that of the second pivotable member 103 aredesigned in a corresponding relation to the conveyance of the 12 cmdisk, so that the conveyance and hence drive of the 8 cm disk cannot bedone at all.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

The present invention has been accomplished in view of the aboveconventional problems and it is an object of the present invention toprovide a slot-in type disk unit, the disk unit permitting drive of twotypes of disks different in diameter, having a function of determiningwhich of the two types of disks has been inserted, being able to remedyany malfunction involved in the conveyance of a small diameter disk, andfacilitating the recovery of the small diameter disk unloaded andexposed from a slot of a bezel.

The present invention achieves the above-mentioned object by adoptingthe following means.

In a first aspect of the present invention there is provided a disk unitwherein a disk inserted by a plurality of arms, the arms being able toconvey two types of disks different in diameter while supporting anouter periphery edge of each of the disks, is loaded to the interior ofthe disk unit by automatic loading, or a disk accommodated in theinterior of the disk unit is unloaded to the exterior of the disk unit,characterized in that a limit switch is used, the limit switch beingactuated by an arm which is pressed by an outer periphery edge of alarge diameter disk or a small diameter disk upon insertion of the diskfrom a slot of a bezel and operates in response thereto, and that theinsertion of the large diameter disk or the small diameter disk isdetermined on the basis of the state of operation of the limit switch.

In a second aspect of the present invention, there is provided, incombination with the above first aspect, a disk unit wherein, whenloading the large diameter disk or the small diameter disk, a conditionfor starting the automatic loading differs depending on the state ofoperation of the limit switch.

In a third aspect of the present invention, there is provided a diskunit wherein a disk inserted by a plurality of arms, the arms being ableto convey two types of disks different in diameter while supporting anouter periphery edge of each of the disks, is loaded to the interior ofthe disk unit by automatic loading, or a disk accommodated in theinterior of the disk unit is unloaded to the exterior of the disk unit,characterized in that a limit switch is used, the limit switch beingactuated by an arm which is pressed by an outer periphery edge of alarge diameter disk or a small diameter disk upon insertion of the diskfrom a slot of a bezel and operates in response thereto, and that on thebasis of the state of operation of the limit switch it is determinedwhether automatic loading of the small diameter disk is possible or not.

In a fourth aspect of the present invention, there is provided, incombination with the above third aspect, a disk unit wherein, when thestate of operation of the limit switch is not coincident with acondition for continuance of the automatic loading of the small diameterdisk, an automatic loading mechanism is operated in reverse to unloadthe small diameter disk to the exterior of the disk unit.

In a fifth aspect of the present invention, there is provided a diskunit wherein a disk inserted by a plurality of arms, the arms being ableto convey two types of disks different in diameter while supporting anouter periphery edge of each of the disks, is loaded to the interior ofthe disk unit by automatic loading, or a disk accommodated in theinterior of the disk unit is unloaded to the exterior of the disk unit,characterized in that, after unloading of a small diameter diskaccommodated in the interior of the disk unit by an automatic loadingmechanism is over, the position where the small diameter disk isunloaded and stands still is advanced by operating the automatic loadingmechanism again.

Thus, according to the present invention, in a slot-in type disk unitpermitting automatic loading and drive of two types of disks differentin diameter, it is possible to determine whether an inserted disk is alarge diameter disk or a small diameter disk, and when loading of asmall diameter disk becomes infeasible for some reason or other, thisstate is detected and the small diameter disk is unloaded forcibly tothe exterior of the disk unit, whereby it is possible to prevent damageof the disk unit and hence possible to improve a mechanical reliabilityof the disk unit. Moreover, when unloading the small diameter disk, theposition where the small diameter disk is exposed from the slot of thebezel and stops is advanced largely, whereby not only the recovery ofthe small diameter disk becomes easier but also the disk unit does notlimit a mechanical design of for example an information device to whichthe disk unit is to be attached.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a slot-in type disk unit embodying thepresent invention;

FIG. 2 is a perspective view showing an interior configuration of thedisk unit of FIG. 1;

FIG. 3 is a perspective view showing the construction of a drivemechanism in the disk unit of FIG. 1;

FIG. 4 is an exploded perspective view showing the construction of aloading slider;

FIG. 5 is an exploded perspective view showing the construction of bothloading slider and guide plate;

FIG. 6 is an exploded perspective view showing the construction of apower transfer mechanism;

FIG. 7 is an exploded perspective view showing the construction of agear disc;

FIG. 8 is a perspective view showing the construction of a rack slider;

FIG. 9 is a first process diagram illustrating in what state a largediameter disk is conveyed;

FIG. 10 is a second process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 11 is a third process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 12 is a fourth process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 13 is a fifth process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 14 is a sixth process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 15 is a seventh process diagram illustrating in what state thelarge diameter disk is conveyed;

FIG. 16 is a first process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 17 is a second process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 18 is a third process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 19 is a fourth process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 20 is a fifth process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 21 is a sixth process diagram illustrating in what state the largediameter disk is conveyed;

FIG. 22 is a seventh process diagram illustrating in what state thelarge diameter disk is conveyed;

FIG. 23 is a first process diagram illustrating in what state a smalldiameter disk is conveyed;

FIG. 24 is a second process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 25 is a third process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 26 is a fourth process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 27 is a fifth process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 28 is a sixth process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 29 is a seventh process diagram illustrating in what state thesmall diameter disk is conveyed;

FIG. 30 is a first process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 31 is a second process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 32 is a third process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 33 is a fourth process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 34 is a fifth process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 35 is a sixth process diagram illustrating in what state the smalldiameter disk is conveyed;

FIG. 36 is a seventh process diagram illustrating in what state thesmall diameter disk is conveyed;

FIG. 37 is a process diagram illustrating an ascending process of a liftframe;

FIG. 38 is a process diagram illustrating a descending process of thelift frame;

FIG. 39 is a diagram illustrating operation modes of the gear disc;

FIG. 40 is a process diagram illustrating operation modes of arms duringconveyance of the large diameter disk;

FIG. 41 is a process diagram illustrating operation modes of a loadingarm;

FIG. 42 is a process diagram illustrating operation modes of the loadingslider and a driven pin;

FIG. 43 is a process diagram showing in what state a lock leverfunctions;

FIG. 44 illustrates a stationary state of disks during unloading;

FIG. 45 is a plan view showing the construction of a disk unit to whichthe present invention is applied;

FIG. 46 is an enlarged perspective view showing the construction of aprincipal portion of the present invention;

FIG. 47 is a plan view showing the construction of the disk unit towhich the present invention is applied;

FIG. 48 illustrates in what state signals are produced when loading thelarge diameter disk;

FIG. 49 illustrates in what state signals are produced when loading thesmall diameter disk;

FIG. 50 illustrates in what state signals are produced in the event ofoccurrence of a malfunction;

FIG. 51 is a diagram for explaining the effect of the present invention;

FIG. 52 is a diagram for explaining the effect of the present invention;

FIG. 53 is a plan view showing a conventional disk unit; and

FIG. 54 is a plan view showing the conventional disk unit.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in detailhereinafter with reference to the accompanying drawings. To facilitateunderstanding of the present invention, constructions related to thegist of the present invention will be included in the followingdescription.

FIG. 1 illustrates an appearance of a slot-in type disk unit 1 embodyingthe present invention. An aperture 2 a is formed centrally of a topplate of a chassis case 2 that is constructed in a shielded condition,and an inwards projecting protuberance 2 b is formed on a periphery edgeportion of the aperture 2 a. A bezel 3 is fixed to a front end of thechassis case 2, and a slot 3 a for insertion therein of both 12 cm disk(hereinafter referred to as the “large diameter disk”) D1 and 8 cm disk(hereinafter referred to as the “small diameter disk”) D2, as well asthrough holes 3 b and 3 c for emergency release, are formed in the bezel3. The bezel 3 is provided with a push-button 4 for unloading the largediameter disk D1 or the small diameter disk D2 accommodated within thedisk unit 1 to the exterior of the unit and an indicator 5 forindicating a state of operation of the disk unit 1.

FIG. 2 is a perspective view of the disk unit with a top plate portionof the chassis case 2 removed. A base panel 6 is disposed within thechassis case 2 and a drive unit A for the large- and small diameterdisks D1, D2 is disposed obliquely downward from the center of the basepanel 6. In the drive unit A, for clamping center holes D1 a and D2 a ofthe large and small diameter disks D1, D2, or for releasing the clampedstate, a lift frame 7 is connected at plural positions to the base panel6 by a known shock-absorbing support structure 8, the lift frame 7 beingconstructed such that a rear end portion thereof positioned centrally ofthe disk unit is vertically pivotable with the front bezel 3 side as afulcrum.

In the rear end portion of the lift frame 7, a clamp head 9 is disposedat a position corresponding to the center of the large or small diameterdisk D1 or D2 that has been loaded and stopped. The clamp head 9 isconstructed integrally with a turntable 10 and is fixed to a drive shaftof a spindle motor 11 disposed just under the clamp head. The large orsmall diameter disk D1 or D2 clamped by a chucking pawl 9 a of the clamphead 9 is driven rotationally by the spindle motor 11 to read or writeinformation.

The reference numeral B denotes a head unit supported by the lift frame7. In the head unit B, a carrier block 13 for reciprocating an opticalpickup 12 in the diametrical direction of the large and small diameterdisks D1, D2 is supported at both ends thereof by guide shafts 14 and 15that are fixed to the lift frame 7. The carrier block 13 is movedforward and backward with a driving force of a sled motor 16 transmittedfrom a gear train 17 to a screw shaft 18 (see FIG. 3).

Plural arms for loading and unloading of the large and small diameterdisks D1, D2 are disposed on a flat surface of the base panel 6 in asurrounding relation to the lift frame 7 and are operated by a drivemechanism disposed on the back side of the base panel 6. Among theplural arms, it is a disk supporting arm 19 that fulfills a mainfunction in loading and unloading of the disks. The disk supporting arm19 is adapted to move pivotally about a rivet pin 20 and not onlysupports rear end sides of the large and small diameter disks D1, D2 butalso keeps accurately the height position of each disk duringconveyance. To this end, the disk supporting arm 19 is provided at a tipthereof with a holder 21, and the rear end sides of the large and smalldiameter disks D1, D2 are held by a recess 21 a of the holder 21.

The reference numeral 22 denotes a loading arm for loading the largediameter disk D1 into the disk unit. The loading arm 22 is pulled by alink lever 24 that is connected to the loading arm through a pivot pin23 and moves pivotally. The loading arm 22 starts pressing a front sideportion with respect to the center of the large diameter disk D1 thathas been inserted by a loading roller 22 a of the loading arm andfunctions to lead the large diameter disk D1 into the disk unit.

A guide arm 25 is adapted to move pivotally about a pivot pin 26 that ismounted rotatably to the base panel 6 and functions to support a sideportion of the small diameter disk D2 and lead it to a predeterminedposition, the small diameter disk D2 being conveyed by a support member25 a that is fixed in a suspended state to a tip of the guide arm 25. Aguide arm 27 is adapted to move pivotally about a rivet pin 28 and notonly functions to support a side portion of the large diameter disk D1and lead it to a predetermined position, the large diameter disk D1being conveyed by a support member 27 a that is fixed in a suspendedstate to a tip of the guide arm 27, but also functions to support a sideportion of the small diameter disk D2 and lead it to a predeterminedposition. On the back side of the base panel 6, an end portion of athird pivotable member 51 and an end portion of an extension spring 53are attached to a pivot pin 27 b provided at a base end portion of theguide arm 27.

A guide arm 29 is adapted to move pivotally about a rivet pin 30 and notonly functions to support a side portion of the small diameter disk D2and lead it to a predetermined position, the small diameter disk D2being conveyed by a support member 29 a that is fixed in an erectedstate to a tip of the guide arm 29, but also functions to support a sideportion of the large diameter disk D1 and locate it to a predeterminedpositions. A work pin 33 a of a link lever 33 that is urged by anextension spring 31 and moves pivotally about a rivet pin 32 is engagedin a slit 29 e of the guide arm 29, so that the tip of the guide arm 29assumes a constantly urged state in the centripetal direction. A guidearm 35 connected through a driven pin 35 b to a guide groove 29 c formedin a rear end portion of the guide arm 29 is adapted to move pivotallyabout a rivet pin 36 and not only functions to support the rear end sideof the small diameter disk D2 through a support member 35 a that isfixed in an erected state to a tip of the guide arm 35 and lead it to apredetermined position, but also functions to support a side portion ofthe small diameter disk D2 and locate it at a predetermined position.

The reference numeral 37 denotes a lock lever that is adapted to movepivotally about a rivet pin 38, thereby permitting an angle 37 a formedat a tip of the lock lever 37 to lock a tongue piece 29 b provided atthe tip of the guide arm 29. The angle 37 a formed at the tip of thelock lever 37 is urged constantly in the centripetal direction by a wirespring 39, but usually a stopper 40 functions to let the lock lever 37stand still at a predetermined position.

The reference numeral 41 denotes a lead wire which is disposed along thelower side of the bezel 3. An end portion of the lead wire 41 isconnected to a rear end portion of the lock lever 37 and a retaining endportion 41 a of the lead wire 41 is bent in an erected state and facesthe slot 3 a of the bezel 3. Therefore, when the large diameter disk D1is inserted from the slot 3 a, the retaining end portion 41 a is pushedby a side portion of the large diameter disk D1, with the result thatthe lead wire 41 moves sideways in parallel with the bezel 3.Consequently, the lock lever 37 is pulled and the angle 37 a formed atthe tip of the lock lever moves pivotally in a centrifugal direction,whereby the tongue piece 29 b of the guide arm 29 can be unlocked.

As a mechanical element exposed onto the flat surface of the base panel6, the reference numeral 42 a denotes a retaining tongue piece of alever arm 42 (see FIGS. 2 and 3), which functions to control theposition of the guide arm 27. As to an operation mode thereof, adetailed description will be given later. Reference numeral 71 denotes aclamp release pin for releasing the clamped state of the large and smalldiameter disks D1, D2 by the clamp head 9.

Mechanical elements are constructed on the back side of the base panel 6to operate the guide arms, etc., thus constructed on the flat surface ofthe base panel 6. The disk unit 1 of the present invention isconstructed so that all of operation controls related to the conveyanceof the large and small diameter disks D1, D2 can be completed by advanceand retreat of a loading slider 43 that is disposed in a side portion ofthe interior of the disk unit and in the longitudinal direction asindicated in phantom line in FIG. 3. The following description is nowprovided about the construction of the loading slider 43 as a mainmechanical element and also about mechanical elements whose operationsare controlled by the loading slider 43.

FIG. 4 shows a state in which the loading slider 43 is overlooked in adirection opposed to the back side of the base panel 6. As shown in thesame figure, the loading slider 43 is formed in the shape of a pillarand a rack gear 43 a is formed in a front end portion of the loadingslider. On the other hand, in a rear end portion of the loading slider43 is formed a guide groove 43 b, the guide groove 43 b comprising anupper-end horizontal portion 43 b-1, a lower-end horizontal portion 43b-2, and an intermediate, stepped, vertical portion 43 b-3, which are incommunication with one another.

A driven pin 45 a of a first pivotable member 45 adapted to movepivotally about a rivet pin 44 is fitted in the upper-end horizontalportion 43 b-1 and a driven pin 47 a of a second pivotable member 47adapted to move pivotally about a rivet pin 46 is fitted in the verticalportion 43 b-3. Further, a work pin 47 b of the second pivotable member47 is fitted in an end through hole 48 a of a driven slider 48.

Guide grooves 43 c-1 and 43 c-2 are formed on both sides of a middleportion of the loading slider 43. A rear end portion of the guide groove43 c-1 is formed with a slant face and front and rear ends of the guidegroove 43 c-2 are also inclined. A driven pin 29 d of the guide arm 29is mounted so as to be positioned in an opening of the inclined rear endportion of the guide groove 43 c-2 in a most advanced state of theloading slider 43.

Reference numeral 43 d denotes a guide groove adapted to pull the linklever 24 so as to operate the loading arm 22 in synchronism withconveyance of the large diameter disk D1. As shown in FIG. 5, a guideslit 49 a is formed in a guide plate 49 fixed to the base panel 6 at aposition overlapping the guide groove 43 d. A driven pin 24 a fixed to atip of the link lever 24 is in an inserted state into both guide groove43 d and guide slit 49 a. Therefore, the guide groove 43 d adapted tomove forward and backward and the guide slit 49 a lying at a fixedposition operate on each other to control the operation of the drivenpin 24 a.

In a side portion of the loading slider 43, which side portion faces thelift frame 7, there is formed a cam groove 43 e to vertically move thedriven pin 7 a that functions to raise and lower the lift frame 7. Thecam groove 43 e comprises a lower portion 43 e-1 for maintaining thelift frame 7 at a low position, a slant portion 43 e-2 for raising orlowering the lift frame 7, and a higher portion 43 e-3 for maintainingthe lift frame 7 at a high position, which are formed in series.

FIG. 6 is an exploded perspective view of a power transfer mechanism asoverlooked from a back side thereof, the power transfer mechanism beingconstructed in the rear portion of the interior of the disk unit. In thepower transfer mechanism, a cam groove 48 c is formed in the drivenslider 48 to raise and lower a driven pin 7 b that functions to raiseand lower the lift frame 7. The cam groove 48 c comprises a lowerportion 48 c-1 for maintaining the lift frame 7 at a low position, aslant portion 48 c-2 for raising or lowering the lift frame 7, and ahigher portion 48 c-3 for maintaining the lift frame 7 at a highposition, which are formed in series.

A work pin 51 a of the third pivotable member 51 adapted to movepivotally about a rivet pin 50 is fitted in an end through hole 48 b ofthe driven slider 48. An end portion 52 a of a link wire 52 is fitted onthe work pin 51 a and an opposite end portion 52 b of the link wire 52is engaged in a through hole 45 b of the first pivotable member 45. Thethird pivotable member 51 is urged counterclockwise in FIG. 6 by theextension spring 53, but when the disk unit is not in operation, thethird pivotable member 51 stands still at its predetermined positionbecause the movement of the work pin 51 a is restricted by the link wire52. Further, a work piece 48 d for actuating the lever arm 42 is formedin a side portion of the end through hole 48 b.

A link arm 54 is connected between the first pivotable member 45 and agear disk that will be described later. The link arm 54 is constructedso that it can expand and contract by a combination of a first link arm54 a connected to the first pivotable member 45 through a connectingmember 55 and a second link arm 54 b urged by an extension spring 56,thereby ensuring the safety of the mechanism during conveyance of thelarge and small diameter disks D1, D2.

FIG. 7 is a perspective view of an end portion of the second link arm 54b as overlooked from the back side of the disk unit. In the same figure,a through hole 54 b-1 formed in the second link arm 54 b, a through hole19 b formed in a rotary base 19 a of the disk supporting arm 19, and athrough hole 59 a formed in a gear disk 59, are pivotally supportedsimultaneously by a pivot pin 57. On the other hand, a center hole 19 cof the disk supporting arm 19 and a center hole 59 b of the gear disk 59are supported simultaneously by the rivet pin 20 that is fixed at oneend thereof to the base panel 6. Further, a retaining piece 19 d of therotary base 19 a faces a retaining window 59 c of the gear disk 59 toprovide an integral combination.

A gear 59 d is formed in part of an outer periphery edge of the geardisk 59 opposed to a side face of the chassis case 2. In an outerperiphery edge of the gear disk 59 opposite to the said outer peripheryedge, there are formed switch starting stepped portions 59 e and 59 f. Alimit switch 60, which is turned ON by the switch starting steppedportions 59 e and 59 f, is mounted on a wiring board (not shown)disposed on the bottom of the chassis case 2 and a switch knob 60 athereof is operated by the switch starting stepped portions 59 e and 59f.

The above-described lever arm 42 is fixed so as to move pivotally abouta rivet pin 61 and its retaining tongue piece 42 a is allowed to facethe surface of the base panel 6 from the opening of the base panel 6.Further, a tip of a spring piece 42 b is brought into contact with anopening wall 6 a of the base panel 6 so that an urging force acting inthe centrifugal direction is generated in a roller 42 c provided at atip of the lever arm 42. According to this construction, the lever arm42 stands still at its predetermined position when the roller 42 c is incontact with a side wall of the driven slider 48, but with a slidingmotion of the driven slider 48, the roller 42 c is pressed by the workpiece 48 d of the driven slider, so that the lever arm 42 movespivotally about the rivet pin 61 and the retaining tongue piece 42 amoves in the centrifugal direction.

Next, a description will be given about a mechanism for pivoting theguide arm 25. The pivot pin 26 provided at a base end as a fulcrum ofthe guide arm 25 is extended to the back side of the base panel 6 and aroller supporting plate 62 is fixed to an end portion of the pivot pin26. Since an extension spring 63 is anchored in a stretched state to theroller supporting plate 62 as shown in FIG. 3, a clockwise urging forcein the same figure is exerted on the guide arm 25, so that the guide arm25 tilts in the centripetal direction. As shown in FIG. 8, a doubleroller 64 disposed on the roller supporting plate 62 has a largediameter portion 64 a and a small diameter portion 64 b that areconstructed coaxially with each other.

In FIG. 8, a rack slider 65 disposed along an inner surface of a sidewall of the chassis case 2 is provided with a rack gear 65 a meshingwith the gear 59 d of the gear disk 59 and moves forward and backward insynchronism with rotation of the gear disk 59. A lower guide piece 65 bis formed on a lower side of an intermediate portion of the rack slider65 and an upper guide piece 65 c is formed on an upper side of the saidintermediate portion. The lower guide piece 65 b guides the largediameter portion 64 a of the double roller 64, while the upper guidepiece 65 c guides the small diameter portion 64 b.

The mechanical elements thus constructed are operated with advance andretreat of the loading slider 43 and a drive mechanism for them isdisposed in a corner portion of the back side of the disk unit as shownin FIG. 3. A loading motor 66 serves as a power source of the drivemechanism and a rotational force of a worm gear 67 of an output shaft ofthe loading motor 66 is transmitted successively from a gear smaller indiameter up to a gear larger in diameter while being reduced in speed bymeans of a gear train comprising double gears 68, 69, and 70. A drivingforce is transmitted to the rack gear 43 a of the loading slider 43 froma small diameter gear of the double gear 70 meshing with the rack gear43 a, whereby the loading slider 43 moves forward or backward.

The following description is now provided about operation modes of thedisk unit 1 of the present invention constructed as above. As describedabove, the disk unit 1 of the present invention is constructed so as topermit conveyance of the large and small diameter disks D1, D2. First, aconveyance mode of the large diameter disk D1 will be described withreference to FIGS. 9 to 22 and a conveyance mode of the small diameterdisk D2 will be described with reference to FIGS. 23 to 36.

FIGS. 9 to 15 are plan views illustrating, with solid lines, mainconstituent portions exposed to the surface of the base panel 6 andillustrating, with broken lines, main constituent portions on the backside of the base panel 6. FIGS. 16 to 22 are bottom views illustrating,with solid lines, main constituent portions exposed to the back side ofthe base panel 6 and illustrating, with broken lines, main constituentportions on the surface side of the base panel 6. Properly speaking, thecam grooves 43 e, 48 c and the driven pins 7 a, 7 b do not appear inFIGS. 9 to 15, but for the convenience of explanation and for easierunderstanding, they are illustrated in those figures.

FIGS. 9 and 16 show a state in which the disk unit is waiting forinsertion of the large diameter disk D1 from the slot 3 a of the bezel 3and the arms stand sill in an initial condition. At this time, the largediameter portion 64 a of the roller 64 of the roller supporting plate 62that is fixed to the pivot pin 26 on the back side of the base panel 6is in abutment against the lower guide piece 65 b of the rack slider 65as shown in FIGS. 8 and 16 and the guide arm 25 is at rest in a positionpivoted in the centrifugal direction by a predetermined amount from aposition most pivoted in the centripetal direction.

This is for the following reason. If there is adopted a constructionwherein the guide arm 25 stops at the position most pivoted in thecentripetal direction and waits for insertion of a disk, when the smalldiameter disk D2 is inserted into the disk unit in proximity to the leftside of the disk unit, the small diameter disk D2 enters the left sideof the support member 25 a and it becomes impossible to convey the smalldiameter disk D2. For preventing the occurrence of such aninconvenience, the guide arm 25 is stopped at a position pivoted in thecentrifugal direction by a predetermined amount from the position mostpivoted in the centripetal direction and is allowed to wait forinsertion of the disk.

Since the base end portion of the guide arm 27 is urged by the extensionspring 53, a force acting to pivot the tip support member 27 a in thecentripetal direction is exerted constantly on the guide arm 27.However, since the third pivotable member 51 connected to the pivot pin27 b stands still at its predetermined position, the guide arm 27 is atrest in its states shown in FIG. 9. This is because the link wire 52stretched between the first pivotable member 45 that is at a standstilland the work pin 51 a of the third pivotable member 51 functions as astopper and inhibits a pivotal movement of the third pivotable member51.

Likewise, the disk supporting arm 19, the guide arms 29, 35 and theloading arm 22 to which power is transmitted with movement of theloading slider 43 are also at rest in the respective states shown inFIG. 9. Further, the driven pin 7 a of the lift frame 7 that is guidedby the cam groove 43 e of the loading slider 43 lies in the lowerportion 43 e-1 of the cam groove 43 e, while the driven pin 7 b of thelift frame 7 that is guided by the cam groove 48 c of the driven slider48 lies in the lower portion 48 c-1 of the cam groove 48 c, so that thelift frame 7 assumes its most descended state as shown in FIG. 37(A).

FIGS. 10 and 17 show a state in which the large diameter disk D1 isinserted from the slot 3 a of the bezel 3 by an operator and its frontend side is put in abutment against both holder 21 of the disksupporting arm 19 and support member 29 a of the guide arm 29. At thistime, the large diameter disk D1 pushes the support member 25 a providedat the tip of the guide arm 25 and moves pivotally in the centrifugaldirection from its position shown in phantom line in FIG. 10. At thesame time, a side portion of the large diameter disk D1 pushes theretaining end portion 41 a of the lead wire 41 and slides in thedirection of arrow in the same figure. As a result, the lock lever 37 ispulled by the lead wire 41 and the angle 37 a formed at the tip of thelock lever 37 moves pivotally in the direction of arrow in the samefigure and is therefore deviated from the locking range for the tonguepiece 29 b provided at the tip of the guide arm 29.

FIGS. 11 and 18 show a further inserted state of the large diameter diskD1 from the above condition by the operator. The disk supporting arm 19and the guide arms 25, 29 are pushed by the large diameter disk D1 andmove pivotally in the centrifugal direction. Consequently, a baseportion of the disk supporting arm 19 rotates from its position shown inFIG. 39(A) up to its position shown in FIG. 39(B) with the rivet pin 20as a fulcrum and the limit switch 60 is actuated by the switch startingstepped portion 59 e of the gear disk 59. At this time, the rack slider65 meshing with the gear disk 59 advances slightly.

The state of generation of signals A1 and A2 outputted from the limitswitch 60 actuated by the gear disk 59 and that of signals B and Coutputted from limit switches LS1 and LS2 that are disposed as shown inFIGS. 45 to 47 as a construction to be described later are detected andan automatic loading start timing is determined. FIG. 48 shows the stateof generation of the aforesaid signals produced with conveyance of thelarge diameter disk D1 and FIG. 49 shows the state of generation of theaforesaid signals produced with conveyance of the small diameter diskD2.

When the limit switch 60 is actuated by the switch starting steppedportion 59 e of the gear disk 59 and the signal A1 turns from ON to OFFas shown in FIG. 48, the signal B from the limit switch LS1 that hadalready been actuated before operation of the limit switch 60 has turnedfrom OFF to ON and the signal C from the limit switch LS2 is OFF. Fromthese conditions it is determined that the large diameter disk D1 hasbeen inserted and at this stage the automatic loading is not started.

When the large diameter disk D1 is further inserted from this state bythe operator into the state shown in FIGS. 12 and 19, the gear disk 59provided at the base portion of the disk supporting arm 19 furtherrotates up to the position shown in FIG. 39(C) and the disk startingstepped portion 59 f turns the switch knob 60 a of the limit switch 60in reverse. At this time, the signal A2 from the limit switch 60 turnsfrom OFF to ON, whereupon a driving current is fed to the loading motor66 to start automatic loading. As a result, the loading slider 43retreats and so does the driven pin 45 a, so that the first pivotablemember 45 moves pivotally about the rivet pin 44 and the first link arm54 a of the link arm 54 advances toward the second link arm 54 b.

Upon arrival at the above state, the guide arm 29 pivots in thecentrifugal direction and the support of the large diameter disk D1 bythe support member 29 a is released. This is because in the state ofFIG. 11 the driven pin 29 d of the guide arm 29 positioned on the slantface of the rear end portion of the guide groove 43 c-1 in the loadingslider 43 undergoes the action of the said slant face with retreat ofthe loading slider 43.

With the foregoing pivotal movement of the first pivotable member 45,the third pivotable member 51 whose pivotal movement is inhibited by thelink wire 52 pivots about the rivet pin 50 under the action of theextension spring 53. As a result, the guide arm 27 pivots in thecentripetal direction and a rear side portion of the large diameter diskD1 is supported by the support member 27 a provided at the front end ofthe guide arm 27. At this time, the link lever 24 is pulled with retreatof the loading slider 43, so that the loading arm 22 pivots in thecentripetal direction and the loading roller 22 a provided at the frontend of the loading arm 22 comes into abutment against and supports afront side portion of the large diameter disk D1. Since the driven pin 7a of the lift frame 7 is in a state of laterally moving in the lowerportion 43 e-1 of the cam groove 43 e, the lift frame 7 stops at itsposition shown in FIG. 37(A).

FIGS. 13 and 20 show a state in which the automatic loading by theloading motor 66 is started and the large diameter disk D1 is beingloaded. When the loading slider 43 further retreats from the state ofFIG. 12, the driven pin 29 d of the guide arm 29 enters the guide groove43 c-1 from the slant portion of the loading slider 43. As a result, theguide arm 29 further pivots in the centrifugal direction and the supportmember 29 a provided at the tip of the guide arm 29 assumes a state freeof contact with a side portion of the large diameter disk D1. FIGS.40(A) to 40(D) show operation modes of the guide arm 29 in a continuousmanner.

As the loading slider 43 moves backward, the link lever 24 is pulled tostart a pivotal movement in the centripetal direction of the loading arm22. FIGS. 41(A) to 41(D) show pivoting states of the loading arm 22 in acontinuous manner. The state of the loading arm 22 shown in FIG. 12corresponds to a shifted state to FIG. 41(B) from an initial state ofFIG. 41(A).

As noted earlier, the driven pin 24 a fixed to the tip of the link lever24 that causes a pivotal movement of the loading arm 22 is inserted intoboth guide groove 43 d of the loading slider 43 and the guide slit 49 aof the guide plate 49, so upon retreat of the loading slider 43, thedriven pin 24 a is held grippingly between the rear-end slant face ofthe guide groove 43 d and a side wall of the guide slit 49 a andtherefore retreats as well. Consequently, the link lever 24 is pulledand the loading arm 22 moves pivotally.

When the loading slider 43 retreats up to its position shown in FIG. 13,the upper-end horizontal portion 43 b-1 of the guide groove 43 b pushesup the driven pin 45 a of the first pivotable member 45, causing thefirst pivotable member 45 to move pivotally about the rivet pin 44 andcausing rotation of the gear disk 59 through the link arm 54. As aresult, the disk supporting arm 19 moves pivotally in the centrifugaldirection, that is, the holder 21 that supports the rear end portion ofthe large diameter disk D1 moves backward in synchronism with theloading of the large diameter disk D1. At this stage, the driven pin 47a of the second pivotable member 47 is sliding along the verticalportion of the guide groove 43 b, so that the second pivotable member 47is at a standstill and so is the driven slider 48.

With the loading of the large diameter disk D1, the support member 27 aprovided at the tip of the guide arm 27 that is urged by the extensionspring 53 in the course of shift from the state of FIG. 12 to the stateof FIG. 13 is pushed back as in FIG. 13 into abutment against theretaining tongue piece 42 a of the lever arm 42 and stops. At this time,the third pivotable member 51 slightly moves pivotally and therefore itswork pin 51 a moves in the centripetal direction through the end throughhole 48 b of the driven slider 48 that stands still, thus resulting inthat the link wire 52 is slightly deflected.

On the other hand, the support member 25 a of the guide arm 25 supportsa front side portion of the large diameter disk D1 and the upper guidepiece 65 c of the rack slider 65 that has advanced with rotation of thegear disk 59 is in a spaced state from the small diameter portion 64 bof the double roller 64. At this time, the driven pin 7 a of the liftframe 7 is in a state of laterally moving through the lower portion 43e-1 of the cam groove 43 e and the driven slider 48 is at rest, so thatthe lift frame 7 still stands still at its position shown in FIG. 37(A).

FIGS. 14 and 21 show a state in which the loading slider 43 furtherretreats from its state shown in FIGS. 13 and 20, the link lever 24 ispulled, causing the loading arm 22 to move pivotally up to its positionshown in FIG. 41(C), and the center of the center hole D1 a of the largediameter disk D1 that has been loaded and the center of the clamp head 9are aligned with each other. On the other hand, the driven pin 29 d ofthe guide arm 29 moves straight through the guide groove 43 c-1 of theloading slider 43, so that the guide arms 29 and 35 are at rest in theirpositions shown in FIG. 14. At this time, the support members 29 a and35 a catch and position the outer periphery edge of the large diameterdisk D1, whereby the center hole D1 a of the large diameter disk D1 andthe clamp head 9 are accurately aligned with each other.

With the retreat of the loading slider 43, the driven pin 45 a of thefirst pivotable member 45 is pushed up to the upper-end horizontalportion 43 b-1 and shifts to the vertical portion 43 b-3, so that thefirst pivotable member 45 moves pivotally up to its position shown inthe drawings, and the disk supporting arm 19 also pivots in thecentrifugal direction with rotation of the gear disk 59 caused by thelink arm 54. The rotation of the gear disk 59 causes a further advanceof the rack slider 65 and the small diameter portion 64 b of the doubleroller 64 strikes on the upper guide piece 65 c, so that the guide arm25 largely pivots in the centrifugal direction and the support of theouter periphery edge of the large diameter disk D1 by the support member25 a is ended. Now, the guide arm 25 is retracted sideways of the liftframe 7 and does not extend over the lift frame 7. Thus, there is nofear of collision between the lift frame 7 that is rising and the guidearm 25.

At this time, the large diameter disk D1 presses the support member 27 aof the guide arm 27, but since the support member 27 a is abuttedagainst the retaining tongue piece 42 a of the lever arm 42 and a stopposition thereof is established, so that the center of the largediameter disk D1 is aligned with the clamp head 9 in the horizontaldirection at this stage. On the other hand, a vertical center of thelarge diameter disk D1 relative to the clamp head 9 is established bythe holder 21 of the disk supporting arm 19 that stands still in thestate shown in FIG. 14 and the loading roller 22 a of the loading arm22.

Thus, according to the disk unit of the present invention, from the timethe automatic loading of the large diameter disk D1 is started untilreaching the state of FIG. 14, the large diameter disk D1 is supportedin at least three positions of its outer periphery edge by the foregoingplural arms and is stopped in the position where the disk as loaded intothe disk unit can be clamped in its center hole D1 a by the clamp head9.

In the course of shift from FIG. 13 to FIG. 14, the driven pin 7 a ofthe lift frame 7 shifts from the lower portion 43 e-1 to the slantportion 43 e-2 and rises with retreat of the cam groove 43 e of theloading slider 43. On the other hand, the driven pin 47 a of the secondpivotable member 47 passes the vertical portion 43 b-3 of the loadingslider 43 and reaches the lower-end horizontal portion 43 b-2 and thesecond pivotable member 47 moves pivotally in the centrifugal direction,so that the work pin 47 b causes the driven slider 48 to movehorizontally, with a consequent horizontal movement of the cam groove 48c. Accordingly, the driven pin 7 b of the lift frame 7 shifts from thelower portion 48 c-1 to the slant portion 48 c-2 and rises and the liftframe 7 starts to rise as shown in FIG. 37(B).

FIGS. 15 and 22 show a final state in which the clamp head 9 clamps thecenter hole D1 a of the large diameter disk D1, thereby permitting driveof the large diameter disk D1. For reaching this state it is necessarythat the loading arm 22 and the guide arm 27 pivot slightly in thecentrifugal direction to terminate the support of the large diameterdisk D1 so as not to be an obstacle to rotation of the disk.

More particularly, at a further retreated and stopped position of theloading slider 43 from the state of FIG. 14, the driven pin 24 a of thelink lever 24 is pushed into a lateral groove in a rear end of the guideslit 49 a at a vertical offset portion of the rear portion of the guidegroove 43 d, so that, as shown in FIG. 41(D), the link lever 24 returnsslightly in the direction opposite to the pulling direction and theloading arm 22 pivots slightly in the centrifugal direction to terminatethe support of the outer periphery edge of the large diameter disk D1 bythe loading roller 22 a.

At the same time, the driven pin 45 a of the first pivotable member 45is slightly pivoted by a slant portion formed at a middle position ofthe vertical portion 43 b-3 of the guide groove 43 b and this pivotalmotion is transmitted to the gear disk 59 through the link arm 54. As aresult, the disk supporting arm 19 pivots slightly in the centrifugaldirection to terminate the support of the outer periphery edge of thelarge diameter disk D1 by the disk supporting arm 19.

On the other hand, the driven pin 47 a of the second pivotable member 47is pushed up largely in the lower-end horizontal portion 43 b-2 of theguide groove 43 b in the loading slider 43, whereby the work pin 47 bpivots in the centrifugal direction, causing the driven slider 48 tomove horizontally, and the end through hole 48 b pulls the work pin 51 aof the third pivotable member 51. As a result, the third pivotablemember 51 pivots slightly and at the same time the work piece 48 dpushes up the roller 42 c of the lever arm 42, whereby the retainingtongue piece 42 a of the lever arm 42 against which the support member27 a of the guide arm 27 is abutted moves backward. Consequently, theguide arm 27 pivots slightly in the centrifugal direction to terminatethe support of the outer periphery edge of the large diameter disk D1 bythe guide arm 27.

At this time, an end portion of the guide groove 43 c-1 of the loadingslider 43 pushes the driven pin 29 d of the guide arm 29, whereby theguide arm 29 pivots slightly. As a result, the support member 29 a ofthe guide arm 29 pivots in the centrifugal direction to completepositioning of the outer periphery edge of the large diameter disk D1.Further, the guide arm 35 connected through the driven pin 35 b to theguide groove 29 c of the guide arm 29 pivots slightly, whereby thesupport member 35 a also pivots in the centrifugal direction to completepositioning of the outer periphery edge of the large diameter disk D1.

In the course of shift from FIG. 14 to FIG. 15, the driven slider 48moves horizontally in synchronism with retreat of the loading slider 43,but the driven pin 7 a of the lift frame 7 shifts from the slant portion43 e-2 of the cam groove 43 e in the loading slider 43 to the higherportion 43 e-3 and the driven pin 7 b shifts from the slant portion 48c-2 of the cam groove 48 c in the driven slider 48 to the higher portion48 c-3.

In this process the lift frame 7 behaves as follows. The lift frame 7rises by the driven pins 7 a and 7 b that rise along the slant portions43 e-2 and 48 c-2, the chucking pawl 9 a of the clamp head 9 comes intoabutment against the center hole D1 a of the large diameter disk D1 andpushes up the large diameter disk D1, as shown in FIG. 37(C), and theperipheral edge of the center hole D1 a comes into abutment against theprotuberance 2 b of the chassis chase 2.

When the driven pins 7 a and 7 b reach the tops of the slant portions 43e-2 and 48 c-2 from the above state, the clamp head 9 is fitted in thecenter hole D1 a of the large diameter disk D1 to complete clamping bythe chucking pawl 9 a, as shown in FIG. 37(D), whereby the largediameter disk D1 is fixed onto the turntable 10. Then, the driven pins 7a and 7 b shift to the higher portions 43 e-3 and 48 c-3, whereby thelift frame 7 descends to its position shown in FIG. 37(E), thuspermitting drive of the large diameter disk D1.

Operation modes of various mechanisms during loading of the largediameter disk D1 by the disk unit 1 of the present invention have beendescribed above, but, during unloading, the mechanisms operate inaccordance with a sequence reverse to the above loading sequence withadvance of the loading slider 43. That is, when unloading of the largediameter disk D1 is started and the loading slider 43 starts to advance,the lift frame 7 once rises and then descends to its initial position,as shown in FIGS. 38(A) to 38(E). In the meantime, the large diameterdisk D1 is stuck up by a clamp release pin 71 as shown in FIG. 38(C),whereby the clamped state by the clamp head 9 is released.

In the above process up to release of the clamp of the large diameterdisk D1, the disk supporting arm 19, loading arm 22 and guide arm 27start moving pivotally in the centripetal direction to support the outerperiphery edge of the large diameter disk D1 as shown in FIG. 14.Subsequently, the large diameter disk D1 is unloaded with the pivotingforce in the centripetal direction of the disk supporting arm 19 and isstopped in a state in which its front end portion is exposed from theslot 3 a of the bezel 3.

Operation modes of the driven pins 24 a, 29 d, 45 a, and 47 a withretreat of the loading slider 43 are shown in a continuous manner inFIGS. 42(A) to 42(F).

Next, operation modes in case of conveying the small diameter disk D2 bythe disk unit of the present invention will be described with referenceto plan views of FIGS. 23 to 29 and bottom views of FIGS. 30 to 36.Properly speaking, the cam grooves 43 e, 48 c and the driven pins 7 a, 7b do not appear in FIGS. 23 to 29, but they are illustrated therein forthe convenience of explanation and for easier understanding.

FIGS. 23 and 30 show a state in which the disk unit is waiting forinsertion therein of the small diameter disk D2 from the slot 3 a of thebezel 3, with the arms being at rest in their initial states. At thistime, the large-diameter portion 64 a of the roller 64 of the rollersupporting plate 62 fixed to the pivot pin 26 on the back side of thebase panel 6 is in abutment against the lower guide piece 65 b of therack slider 65 as shown in FIGS. 8 and 30 and the guide arm 25 is atrest in a position pivoted in the centrifugal direction by apredetermined amount from the position most pivoted in the centripetaldirection.

This is for the following reason. According to a construction whereinthe guide arm 25 stops at the most pivoted position in the centraldirection and waits for insertion of the disk, when the small diameterdisk D2 is inserted near the left side of the disk unit, the smalldiameter disk D2 enters the left side of the support member 25 a, makingthe conveyance of the small diameter disk D2 impossible. To prevent theoccurrence of this inconvenience, the guide arm 25 is stopped at aposition pivoted in the centrifugal direction by a predetermined amountfrom the most pivoted position in the centripetal direction and isallowed to wait for insertion of the disk. The state of waiting forinsertion of the small diameter disk D2 shown in FIGS. 23 and 30 iscoincident with the state of waiting for insertion of the large diameterdisk D1 shown in FIGS. 9 and 16.

Since the base end portion of the guide arm 27 is urged by the extensionspring 53, a force acting to pivot the tip support member 27 a in thecentripetal direction is always exerted on the guide arm 27, but thethird pivotable member 51 connected to the pivot pin 27 b is at rest inits predetermined position and the guide arm 27 stands still in itsstate shown in FIG. 23. This is because the link wire 52 stretchedbetween the first pivotable member 45 that is at a standstill and thework pin 51 a of the third pivotable member 51 functions as a stopper toinhibit a pivotal motion of the third pivotable member 51.

Likewise, the disk supporting arm 19, the guide arms 29, 35 and theloading arm 22 are also at rest in their states shown in FIG. 23. Thedriven pin 7 a of the lift frame 7 that is guided by the cam groove 43 eof the loading slider 43 lies in the lower portion 43 e-1 of the camgroove 43 e, while the driven pin 7 b of the lift frame 7 that is guidedby the cam groove 48 c of the driven slider 48 lies in the lower portion48 c-1 of the cam groove 48 c, so that the lift frame 7 is in its mostdescended state as shown in FIG. 37(A).

FIGS. 24 and 31 show a state in which the small diameter disk D2 isinserted from the slot 3 a of the bezel 3 by the operator and the frontend side of the small diameter disk D2 is abutted against the holder 21of the disk supporting arm 19. In the insertion of the small diameterdisk D2 into the slot 3 a at this stage, if the small diameter disk D2is offset to the left in FIG. 24, the left side portion of the front endof the small diameter disk D2 contacts the support member 25 a of theguide arm 25 and is pushed back, whereby it is possible to preventdislodgment of the small diameter disk D2 from the conveyance path.

In the inserting operation of the small diameter disk D2, if the rightside portion of the front end of the small diameter disk D2 presses thesupport member 29 a of the guide arm 29 and causes the support member topivot in the centrifugal direction as shown in FIG. 43(A), the tonguepiece 29 b is locked by the angle 37 a of the lock lever 37, which is atrest in its predetermined position without pivoting as in FIG. 43(B).Therefore, also in this case it is possible to prevent dislodgment ofthe small diameter disk D2 from the conveyance path. That is, the smalldiameter disk D2 is guided to the center of the disk unit by bothsupport member 25 a of the guide arm 25 and support member 29 a of theguide arm 29.

FIGS. 25 and 32 show a further inserted state of the small diameter diskD2 from the above condition by the operator. The disk supporting arm 19is pressed by the small diameter disk D2 and pivots in the centrifugaldirection, further, the support member 25 a of the guide arm 25, whichis interlocked with the pivotal movement of the disk supporting arm 19and the support member 29 a of the guide arm 29 come into contact with aside portion of the small diameter disk D2. As a result, the smalldiameter disk D2 assumes a three-point supported state by the supportmembers 25 a, 29 a and the holder 21 of the disk supporting arm 19.

The base portion of the disk supporting arm 9 turns about the rivet pin0 from its position shown in FIG. 39(A) up to its position shown in FIG.39(B), the limit switch 60 is actuated by the switch starting steppedportion 59 e of the gear drum 59, and when the signal A1 turns from ONto OFF as in FIG. 48, the signal B indicating that the limit switch LS1has not been actuated before is kept OFF. From these conditions it isdetermined that the small diameter disk D2 has been inserted, and atthis instant a driving current is fed to the loading motor 66 to startautomatic loading. At this time, the component of force F1 a induced bypressing of the support member 29 a of the guide arm 29 and thecomponent of force F1 b induced by pressing of the support member 25 aof the guide arm 25 under the action of the extension spring 63 are in astate of acting strongly, so that a resultant force F2 acting to movethe small diameter disk D2 in the loading direction is developed, thuspermitting automatic loading by the loading motor 66.

FIGS. 26 and 33 show a state in which the automatic loading is startedby the loading motor 66 and the small diameter disk D2 has been loaded.When the loading slider 43 further retreats from the state shown in FIG.25, the driven pin 29 d of the guide arm 29 enters the guide groove 43c-2 of the loading slider 43. At this time, the support member 29 d isguided by the slant portion of the guide groove 43 c-2 and moves adistance corresponding to the slant distance and the support member 29 apivots up to its illustrated position under loading of the smalldiameter disk D2. At this time, under the action of the extension spring63 the guide arm 25 also pivots to its illustrated position while thesmall diameter disk D2 is being loaded.

When the loading slider 43 retreats up to its position shown in FIG. 26,the upper-end horizontal portion 43 b-1 of the guide groove 43 b pushesup the driven pin 45 a of the first pivotable member 45, causing thefirst pivotable member 45 to pivot about the rivet pin 44 and therebycausing the gear disk 59 to rotate through the link arm 54. As a result,the disk supporting arm 19 pivots in the centrifugal direction, that is,the holder 21 that supports the rear end portion of the small diameterdisk D2 retreats in synchronism with loading of the small diameter diskD2. At this stage, the driven pin 47 a of the second pivotable member 47is sliding along the vertical portion of the guide groove 43 b, so thatthe second pivotable member 47 stands still and so does the drivenslider 48.

Thus, with the pivotal movement of the first pivotable member 45, thethird pivotable arm 51 also pivots under the action of the extensionspring 53, so that the guide arm 27 pivots about the rivet pin 28 andits support member 27 a comes into abutment against the small diameterdisk D2. At this time, the driven pin 7 a of the lift frame 7 is movinglaterally through the lower portion 43 e-1 of the cam groove 43 e andthe driven slider 48 is at rest, so that the lift frame 7 remains in itsposition shown in FIG. 37(A).

FIGS. 27 and 34 show a state in which the loading slider 43 furtherretreats from its state shown in FIGS. 26 and 33 and the loading of thesmall diameter disk D2 is continued. The guide arm 29 does not pivotbut, in accordance with the amount of movement of the loading slider 43,the disk supporting arm 19 pivots in the centrifugal direction and theguide arms 25 and 27 pivot in the centripetal direction to support thesmall diameter disk D2.

FIGS. 28 and 35 show a state in which the loading slider 43 furtherretreats from its state shown in FIGS. 27 and 34 and the center of thecenter hole D2 a of the small diameter disk D2 and that of the clamphead 9 are aligned with each other, bringing the disk to a stop. In theprocess up to such a state, as the loading slider 43 retreats, the disksupporting arm 19 pivots largely in the centrifugal direction toterminate the support of the outer periphery edge of the small diameterdisk D2 and as a result of this pivotal movement the gear disk 59 causesthe rack slider 65 to move forward. Consequently, the small diameterportion 64 a of the double roller 64 strikes on the upper guide piece 65c of the rack slider 65 and hence the guide arm 25 pivots largely in thecentrifugal direction to terminate the support of the outer peripheryedge of the small diameter disk D2. Now, the guide arm 25 is retractedsideways of the lift frame 7 and does not extend onto the lift frame 7.

In the above condition, the outer periphery edge of the small diameterdisk D2 is three-point supported by the support member 27 a of the guidearm 27, the support member 29 a of the guide arm 29 and the supportmember 35 a of the guide arm 35. In the process up to this state thepressing force of the support member 27 a of the guide arm 27 based onthe action of the extension spring 53 is exerted on the small diameterdisk D2, whereby the loading of the disk D2 is continued.

In the process from FIG. 27 to FIG. 28, as the cam groove 43 e of theloading slider 43 retreats, the driven pin 7 a of the lift frame 7shifts from the lower portion 43 e-1 to the slant portion 43 e-2 andassumes to rising state. On the other hand, the driven pin 47 a of thesecond pivotable member 47 passes the vertical portion 43 b-3 of theloading slider 43 and reaches the lower-end horizontal portion 43 b-2,causing the second pivotable member 47 to pivot in the centrifugaldirection, so that the work pin 47 b causes the driven slider 48 to movehorizontally and at the same time the cam groove 48 c moveshorizontally. As a result, the driven pin 7 b of the lift frame 7 shiftsfrom the lower portion 48 c-1 to the slant portion 48 c-2 and assumes arising state and the lift frame 7 starts to rise as shown in FIG. 37(B).

FIGS. 29 and 35 show a final state in which the clamp head 9 clamps thecenter hole D2 a of the small diameter disk D2, permitting drive of thesmall diameter disk D2. For achieving this state it is necessary thatthe guide arms 27, 29, and 35 pivot and terminate the support of thesmall diameter disk D2 so as not to be an obstacle to rotation of thesmall diameter disk D2.

That is, in the further retreated and stopped position of the loadingslider 43 from the state of FIG. 28, the driven pin 47 a is pushed up bythe lower-end horizontal portion 43 b-2 and the second pivotable member47 pivots in the centrifugal direction. As a result, the work pin 51 aconnected to the end through hole 48 b of the driven slider 48 is pulledand the third pivotable member 51 pivots in the centripetal direction,whereby the guide arm 27 is pivotally moved in the centrifugal directionto terminate the support of the small diameter disk D2.

On the other hand, the driven pin 29 d of the guide arm 29 reaches theslant portion at the terminal end of the guide groove 43 c-2 in theloading slider 43 and therefore the guide arm 29 pivots slightly in thecentrifugal direction, so that the support of the small diameter disk D2by the support member 29 a is ended. With this pivotal movement of theguide arm 29, the driven pin 35 b connected to the guide groove 29 c ofthe guide arm 29 is operated to pivot the guide arm 35 slightly in thecentrifugal direction, thereby terminating the support of the smalldiameter disk D2.

In the process from FIG. 28 to FIG. 29, the driven slider 48 moveshorizontally in synchronism with retreat of the loading slider 43, butthe driven pin 7 a of the lift frame 7 shifts from the slant portion 43e-2 of the cam groove 43 e in the loading slider 43 to the higherportion 43 e-3 and the driven pin 7 b shifts from the slant portion 48c-2 of the cam groove 48 c in the driven slider 48 to the higher portion48 c-3.

In this process the lift frame 7 behaves as follows. The lift frame 7rises by the driven pins 7 a and 7 b that rise by the slant portions 43e-2 and 48 c-2, then, as shown in FIG. 37(C), the chucking pawl 9 a ofthe clamp head 9 comes into abutment against the center hole D2 a of thesmall diameter disk D2 and pushes up the small diameter disk D2, so thatthe peripheral edge of the center hole D2 a comes into abutment againstthe protuberance 2 b of the chassis case 2.

When the driven pins 7 a and 7 b reach the tops of the slant portions 43e-2 and 48 c-2 from the above condition, as shown in FIG. 37(D), theclamp head 9 is fitted in the center hole D2 a of the small diameterdisk D2 to complete clamping by the chucking pawl 9 a and the smalldiameter disk D2 is fixed thereby onto the turntable 10. As the drivenpins 7 a and 7 b shift to the higher portions 43 e-3 and 48 c-3, thelift frame 7 descends to its position shown in FIG. 37(E), thuspermitting drive of the small diameter disk D2.

Operation modes of various mechanisms during loading of the smalldiameter disk D2 by the disk unit 1 of the present invention has beendescribed above, but for unloading of the disk the mechanisms operatewith advance of the loading slider 43 in accordance with a sequencereverse to the above loading sequence. That is, when the unloading ofthe small diameter disk D2 is started and the loading slider 43 startsto advance, the lift frame 7 once rises and then descends to its initialposition, as shown in FIGS. 38(A) to 38(E). In the meantime, the smalldiameter disk D2 is stuck up by the clamp release pin 71 as shown inFIG. 38(C), whereby the clamped condition by the clamp head 9 isreleased.

In the process up to unclamping of the small diameter disk D2 performedin the above manner, the guide arms 25, 27, and 29 pivot in thecentripetal direction and assume the state shown in FIG. 28 in whichthey support the outer periphery edge of the small diameter disk D2.Subsequently, operations are performed in a sequence reverse to theabove sequence, like FIGS. 27 to 24, during which the small diameterdisk D2 is unloaded with the pivoting force in the centripetal directionof the disk supporting arm 19 until the front end portion thereof isexposed from the slot 3 a of the bezel 3 and then stops.

Next, a main construction of the present invention will be concretelydescribed. FIG. 44 shows a state in which the large diameter disk D1shown in phantom line and the small diameter disk D2 have been unloadedfrom the interior of the disk unit 1 described above and are at astandstill. In both cases of the large and small diameter disks D1, D2,the position where each disk stops in an exposed state of its front endportion from the bezel 3 after unloaded is determined by the mostpivoted and stopped position of the disk supporting arm 19 in thecentripetal direction, so that the greater part of the large diameterdisk D1 is exposed, while as to the small diameter disk D2, only aslight portion of its front end is exposed as shown in the same figure.

When the operator takes out the small diameter disk D2, which is in sucha state from the disk unit, the operator pulls out the disk whilepicking a slight portion of the front end of the small diameter disk D2with fingertips. However, in various information devices wherein thedisk unit is installed, for example if a liquid crystal monitor isdisposed so as to cover the bezel 3, the space in bezel 3 portionbecomes narrow and it becomes more difficult to pull out the smalldiameter disk D2. If an attempt is made to avoid such a difficulty, itbecomes impossible to improve the versatility in mechanical design of aninformation device or the like in which the disk unit is installed.

According to the present invention, in view of the above-mentionedpoint, when unloading the small diameter disk D2 in the disk unit 1constructed as above, the front end portion of the small diameter diskD2 is exposed in a larger amount than in a steady state from the bezel3, whereby the operability at the time of recovery of the small diameterdisk D2 is improved and the disk unit can be installed in any type ofinformation device. That is, since a supplementary unloading operationis added only in case of unloading the small diameter disk D2, it isnecessary to provide a construction for recognizing that the smalldiameter disk is loaded.

FIG. 45 shows a construction wherein limit switches LS1 and LS2 areadded to the disk unit 1 constructed as above, and FIG. 46 shows anenlarged state of this portion. As shown in FIG. 46, there are disposedlimit switches LS1 and LS2 whose switch knobs are operated by a pivotalmovement of a work pin 64 c extended from the small diameter portion 64b of the double roller 64. As shown in FIG. 45, in a state in which thelarge diameter disk D1 is inserted from the slot 3 a of the bezel 3 andautomatic loading is performed, the limit switch LS1 is operated, whilein the state of FIG. 47 in which the small diameter disk D2 is insertedand automatic loading is performed, the limit switch LS2 is operated.

On the basis of the state of operation of the thus-disposed limitswitches LS1, LS2 and the limit switch 60 it is determined whether theinserted disk is the large diameter disk D1 or the small diameter diskD2. That is, in FIG. 48, the signal outputted when the limit switch 60is actuated by the switch starting stepped portion 59 e of the gear disk59 is made a signal A1, while the signal outputted when the limit switch60 is actuated by the switch starting stepped portion 59 f is made asignal A2. Further, the signal outputted when the limit switch LS1 isactuated is made a signal B and the signal outputted when the limitswitch LS2 is actuated is made a signal C.

The state of generation of the signal outputted from each limit switchis detected at the beginning of automatic loading and is compared with apredetermined coincidence condition. FIG. 48 shows the state of signalsduring the process after insertion of the large diameter disk D1 untilautomatic loading. When the large diameter disk D1 is inserted from theslot 3 a of the bezel 3, the guide arm 25 is moved pivotally in thecentrifugal direction, so that the limit switch LS1 is actuated and thesignal B turns from OFF to ON. As to the limit switch LS2, it is notactuated when the large diameter disk D1 is inserted because the guidearm 25 does not pivot in the centripetal direction, and the signal Cfrom the limit switch LS2 is kept OFF.

On the other hand, when the limit switch 60 is actuated by the switchstarting stepped portion 59 e upon rotation of the gear disk 59, whichis induced by a pivotal movement in the centrifugal direction of thedisk supporting arm 19, the signal A1 from the limit switch 60 turnsfrom ON to OFF, but since the signal B from the limit switch LS1 thathad already operated before operation of the limit switch 60 is ON, itis determined that the large diameter disk D1 has been inserted. Whenthe gear disk 59 further rotates and the limit switch 60 is againactuated by the switch starting stepped portion 59 f, the signal A2 fromthe limit switch 60 turns from OFF to ON. This state is detected and anelectric current of a high potential flows in the loading motor 66,whereby automatic loading of the large diameter disk D1 is started.

Next, the state of generation of each signal in automatic loading of thesmall diameter disk D2 that is shown in FIG. 47 will be described withreference to FIG. 49. As described above, automatic loading of the smalldiameter disk D2 is started in accordance with the signal A1 that isoutputted when the limit switch 60 is actuated by the switch startingstepped portion 59 e of the gear disk 59. At this time, the guide arm 25pivots in the centripetal direction and does not pivot in thecentrifugal direction, so that the signal B from the limit switch LS1 iskept OFF.

In the course of this automatic loading, the limit switch LS2 isactuated and the signal C from the limit switch LS2 turns from OFF toON, further, the signal A2 from the limit switch 60 actuated by theswitch starting stepped portion 59 f of the gear disk 59 turns from OFFto ON. Such a state of signal generation is determined to be a state inwhich the small diameter disk D2 is being normally loaded automatically,and the subsequent automatic loading operation is continued.

Thus, when the limit switch LS2 is actuated and the associated signal Cturns from OFF to ON, it is determined that the small diameter disk D2has been inserted, and this result is stored in an electric controlsystem. The determination of the type of the inserted disk may be donewithout using the limit switches described above. For example, there maybe adopted a method wherein a control signal for driving the spindlemotor 11 is monitored and the type of the inserted disk is determinedfrom a driving current or from a time width up to arrival at aconstant-speed rotation.

When the disk unit 1 that is in operation while recognizing the smalldiameter disk D2 receives a command for unloading the small diameterdisk D2, the loading slider 43 advances and the small diameter disk D2is unloaded up to its position shown in FIG. 44 by operations of theguide arms reverse to the loading operations, then the small diameterdisk D2 stops.

Now, a description will be given about a mode of operation of theautomatic loading of the large and small diameter disks D1, D2, which isperformed in the above manner. First, in the case where the start ofautomatic loading of the large diameter disk D1 is set at a time pointwhen the limit switch 60 shown in FIG. 11 is actuated by the switchstarting stepped portion 59 e of the gear disk 59, the component offorce F1 a induced by pressing of the loading roller 22 a and thecomponent of force F1 b induced by pressing of the support member 25 aof the guide arm 25 lie substantially near the center of the largediameter disk D1 in the disk inserting direction, therefore, theresultant force of the two is extremely small, giving rise to theproblem that the loading operation cannot be done to a satisfactoryextent. For this reason, the start of automatic loading of the largediameter disk D1 is set at a time point when the limit switch 60 isactuated in reverse by the switch starting stepped portion 59 f of thegear disk 59.

On the other hand, in the case of the small diameter disk D2, even ifthe whole of the small diameter disk D2 is pushed into the disk unit,the amount of pivotal movement of the disk supporting arm 19 is smalland the limit switch 60 does not assume a state in which it is operatedin reverse by the switch starting stepped portion 59 f of the gear disk59. Therefore, the start of automatic loading of the small diameter diskD2 is set at a time point when the limit switch 60 is actuated by theswitch starting stepped portion 59 e of the gear disk 59.

Thus, in the case where the inserted disk is the large diameter disk D1,automatic loading is started when the large diameter disk D1 has beenfully inserted, that is, automatic loading is started at a largelypivoted stage of the disk supporting arm 19, while in the case where theinserted disk is the small diameter disk D2, automatic loading isstarted in an initial stage of disk insertion, i.e., in a slightlypivoted stage of the disk supporting arm 19.

With the above operations, it is determined that the system hascompleted the normal unloading operation for the small diameter disk D2,and the automatic loading mechanism is again operated by driving theloading motor 66. As a result, the support member 25 a of the guide arm25, which pivots in the centripetal direction and the support member 29a of the guide arm 29 abut and press a rear side edge of the smalldiameter disk D2, so that the small diameter disk D2 advances up to itsposition shown in FIG. 51.

That is, the driven pin 29 d of the guide arm 29 is guided by the slantportion of the guide groove 43 c-2 of the loading slider 43, causing theguide arm 29 to move pivotally, whereby the support member 29 a of theguide arm 29 pivots in the centripetal direction. Further, as the rackslider 65 advances, the roller large diameter portion 64 a of the rollersupporting plate 62 moves away from the lower guide piece 65 b of therack slider 65. As a result, the roller supporting plate 62 pivots underthe biasing force of the extension spring 63 and the support member 25 aof the guide arm 25 fixed to the roller supporting plate 62 pivots inthe centripetal direction.

Thereafter, the loading slider 43 advances from its retreated positionup to its initial position, so that each guide arm stands still in thedisk waiting state shown in FIG. 52. As a result, the front end portionof the small diameter disk D2 is exposed largely from the slot 3 a ofthe bezel 3.

In the above series of operations, the position of the small diameterdisk D2 upon completion of the first loading operation shown in FIG. 44lies on the unloading direction side with respect to its position at thebeginning of automatic loading shown in FIG. 25. When the loadingmechanism is operated from the state shown in FIG. 44, the supportmember 25 a of the guide arm 25 and the support member 29 a of the guidearm 29 come into abutment against the small diameter disk D2 at aposition lying on the disk inserting direction side with respect to thecenter of the disk.

Thus, according to the present invention, both large and small diameterdisks D1, D2 can be loaded automatically by the plural guide arms;besides, when unloading the small diameter disk D2 accommodated withinthe disk unit, the small diameter disk D2 can be exposed largely fromthe slot 3 a of the bezel 3, so that the recovery of the disk becomeseasier and the slot-in type disk unit of the invention can be madehighly versatile without limiting the mechanical design of aninformation device or the like in which the disk unit is to beinstalled.

Next, a description will be given concretely about a construction fordetermining the type of the inserted disk. FIG. 45 shows a constructionwherein limit switches LS1 and LS2 are added to the disk unit 1constructed as above, and FIG. 46 shows an enlarged state of thisportion. As shown in FIG. 46, there are disposed limit switches LS1 andLS2 whose switch knobs are operated by a pivotal movement of a work pin64 c extended from the small diameter portion 64 b of the double roller64. As shown in FIG. 45, in a state in which the large diameter disk D1is inserted from the slot 3 a of the bezel 3 and automatic loading isperformed, the limit switch LS1 is operated, while in the state of FIG.47 in which the small diameter disk D2 is inserted and automatic loadingis performed, the limit switch LS2 is operated.

On the basis of the state of operation of the thus-disposed limitswitches LS1, LS2 and the limit switch 60 it is determined whether theinserted disk is the large diameter disk D1 or the small diameter diskD2. That is, in FIG. 48, the signal outputted when the limit switch 60is actuated by the switch starting stepped portion 59 e of the gear disk59 is made a signal A1, while the signal outputted when the limit switch60 is actuated by the switch starting stepped portion 59 f is made asignal A2. Further, the signal outputted when the limit switch LS1 isactuated is made a signal B and the signal outputted when the limitswitch LS2 is actuated is made a signal C.

The state of generation of the signal outputted from each limit switchis detected at the beginning of automatic loading and is compared with apredetermined coincidence condition. FIG. 48 shows the state of signalsduring the process after insertion of the large diameter disk D1 untilautomatic loading. When the large diameter disk D1 is inserted from theslot 3 a of the bezel 3, the guide arm 25 is moved pivotally in thecentrifugal direction, so that the limit switch LS1 is actuated and thesignal B turns from OFF to ON. As to the limit switch LS2, it is notactuated when the large diameter disk D1 is inserted because the guidearm 25 does not pivot in the centripetal direction, and the signal Cfrom the limit switch LS2 is kept OFF.

On the other hand, when the limit switch 60 is actuated by the switchstarting stepped portion 59 e upon rotation of the gear disk 59, whichis induced by a pivotal movement in the centrifugal direction of thedisk supporting arm 19, the signal A1 from the limit switch 60 turnsfrom ON to OFF, but since the signal B from the limit switch LS1 whichhad already operated before operation of the limit switch 60 has turnedfrom OFF to ON, it is determined that the large diameter disk D1 hasbeen inserted, and at this stage a driving current is not fed to theloading motor 66. When the gear disk 59 further rotates and the limitswitch 60 is again actuated by the switch starting stepped portion 59 f,the signal A2 from the limit switch 60 turns from OFF to ON, whereupon adriving current is fed to the loading motor 66 to start automaticloading of the large diameter disk D1.

Next, the state of generation of each signal in automatic loading of thesmall diameter disk D2 that is shown in FIG. 47 will be described withreference to FIG. 49. As described above, automatic loading of the smalldiameter disk D2 is started in accordance with the signal A1 which isoutputted when the limit switch 60 is actuated by the switch startingstepped portion 59 e of the gear disk 59. At this time, the guide arm 25pivots in the centripetal direction and does not pivot in thecentrifugal direction, so that the signal B from the limit switch LS1 iskept OFF.

In the course of this automatic loading, the limit switch LS2 isactuated and the signal C from the limit switch LS2 turns from OFF toON, further, the signal A2 from the limit switch 60 actuated by theswitch starting stepped portion 59 f of the gear disk 59 turns from OFFto ON. Such a state of signal generation is determined to be a state inwhich the small diameter disk D2 is being normally loaded automatically,and the subsequent automatic loading operation is continued.

Now, a description will be given about a mode of operation of theautomatic loading of the large and small diameter disks D1, D2, which isperformed in the above manner. First, in the case where the start ofautomatic loading of the large diameter disk D1 is set at a time pointwhen the limit switch 60 shown in FIG. 11 is actuated by the switchstarting stepped portion 59 e of the gear disk 59, the component offorce F1 a induced by pressing of the loading roller 22 a and thecomponent of force F1 b induced by pressing of the support member 25 aof the guide arm 25 lie substantially near the center of the largediameter disk D1 in the disk inserting direction, therefore, theresultant force of the two is extremely small, giving rise to theproblem that the loading operation cannot be done to a satisfactoryextent. For this reason, the start of automatic loading of the largediameter disk D1 is set at a time point when the limit switch 60 isactuated in reverse by the switch starting stepped portion 59 f of thegear disk 59.

On the other hand, in the case of the small diameter disk D2, even ifthe whole of the small diameter disk D2 is pushed into the disk unit,the amount of pivotal movement of the disk supporting arm 19 is smalland the limit switch 60 does not assume a state in which it is operatedin reverse by the switch starting stepped portion 59 f of the gear disk59. Therefore, the start of automatic loading of the small diameter diskD2 is set at a time point when the limit switch 60 is actuated by theswitch starting stepped portion 59 e of the gear disk 59.

Thus, in the case where the inserted disk is the large diameter disk D1,automatic loading is started when the large diameter disk D1 has beenfully inserted, that is, automatic loading is started at a largelypivoted stage of the disk supporting arm 19, while in the case of wherethe inserted disk is the small diameter disk D2, automatic loading isstarted in an initial state of disk insertion, i.e., in a slightlypivoted stage of the disk supporting arm 19.

FIG. 50 shows the state of signals outputted when it becomes impossibleto continue automatic loading of the small diameter disk in theconstruction described above. It is assumed that the cause of thiscondition will probably be a malfunction of a mechanical elementassociated with automatic loading or the execution of such an operationby the operator as pulling back the small diameter disk D2 being loaded,and the safety of the disk unit is ensured.

Also in the case of FIG. 50, automatic loading is started upon turningfrom ON to OFF of the signal A1, which is outputted when the limitswitch 60 is actuated by the switch starting stepped portion 59 e of thegear disk 59 upon insertion of the small diameter disk D2. At thisinstant, for example, if a force acting to pull back the small diameterdisk D2 in the unloading direction is applied to the disk D2, thepivotal movement of the guide arm 25 in the centripetal direction isstopped or, conversely, the guide arm 25 is pivoted in the centrifugaldirection, with the result that the limit switch LS2 turns OFF.

Once such a state is reached, the signal C from the limit switch LS2,which must be ON upon turning from OFF to ON of the signal A2 is OFF,which is different from the preset signal condition, so that the systemimmediately determines this state to be an abnormal state. Once anabnormal state is thus detected, the drive mechanism which has so farbeen operated to load the small diameter disk automatically in theloading direction starts operating in reverse in accordance with acommand issued from the system, that is, starts unloading of the smalldiameter disk D2, whereby it is possible to avoid the occurrence of amalfunction.

Thus, according to the present invention, not only automatic loading ofboth large and small diameter disks can be done by plural guide arms,but also it is possible to determine whether the inserted disk is thelarge or the small diameter disk, whereby it is possible to prevent theoccurrence of a malfunction in automatic loading of the small diameterdisk and hence possible to provide a slot-in type disk unit improved inmechanical reliability.

While illustrative embodiments have been illustrated and described, itwill be appreciated that various changes can be made therein withoutdeparting from the spirit and scope of the invention.

1. A disk unit, comprising: a plurality of arms configured to conveyboth a large diameter disk or a small diameter disk to the interior ofthe disk unit while supporting an outer periphery edge of the conveyeddisk during automatic loading, and configured to remove the conveyeddisk from the interior of the disk unit to the exterior of the disk unitduring automatic unloading; at least a first limit switch and a secondlimit switch; and a guide arm located to pivot when pressed by an outerperiphery edge of the conveyed disk upon insertion of the conveyed diskfrom a slot of a bezel, and to selectively actuate the first limitswitch or the second limit switch based on at least the size of theconveyed disk; wherein the first limit switch is actuated by the guidearm and the second limit switch is not actuated by the guide arm uponinsertion of the large diameter disk, and wherein the second limitswitch is actuated by the guide arm and the first limit switch is notactuated by the guide arm upon insertion of the small diameter disk, andwherein whether the conveyed disk is either the large diameter disk orthe small diameter disk is determined on the basis of a state ofoperation of the at least first limit switch and the second limitswitch.
 2. The disk unit according to claim 1, wherein a condition forstarting the automatic loading differs depending on the state ofoperation of at least one of the first limit switch and the second limitswitch.
 3. The disk unit according to claim 1, wherein the guide arm ismoved pivotally in a first direction when the conveyed disk is the largediameter disk and is moved pivotally in a second direction opposite tothe first direction when the conveyed disk is the small diameter disk,and wherein the guide arm selectively actuates the first limit switch orthe second limit switch as to either the first direction or the seconddirection where the guide arm moves pivotally.
 4. A disk unit includingan automatic loading mechanism, the automatic loading mechanismcomprising: a plurality of arms configured to convey both a largediameter disk or a small diameter disk to the interior of the disk unitwhile supporting an outer periphery edge of the conveyed disk duringautomatic loading, and to remove the conveyed disk from the interior ofthe disk unit to the exterior of the disk unit during automaticunloading; at least two limit switches; and a guide arm located to pivotwhen pressed by an outer periphery edge of the conveyed disk uponinsertion of the conveyed disk from a slot of a bezel, and toselectively actuate one of the at least two limit switches when thelarge diameter disk or the small diameter disk is conveyed; and whereinon the basis of a state of operation of the one actuated limit switch itis determined whether automatic loading of the small diameter disk ispossible.
 5. The disk unit according to claim 4, wherein, when the stateof operation of the one actuated limit switch indicates that automaticloading of the small diameter disk is not possible, the automaticloading mechanism is operated in reverse to unload the small diameterdisk to the exterior of the disk unit.
 6. The disk unit according toclaim 4, wherein the guide arm is moved pivotally in a first directionwhen the conveyed disk is the large diameter disk and is moved pivotallyin a second direction opposite to the first direction when the conveyeddisk is the small diameter disk, and wherein the guide arm selectivelyactuates one of the at least two limit switches as to either the firstdirection or the second direction where the guide arm moves pivotally.